Grinding wheel dressing apparatus



May 7, 1968 B. w. WEISEL GRINDING WHEEL DRESSING APPARATUS 3 Sheets-Sheet 1 Filed March 5, 1966 May 7, 1968 B. w. WEISEL GRINDING WHEEL DRESSING APPARATUS 5 Sheets-Sheet 5;

Filed March 5, 1966 FIGS Laz w QMMAMMS ATTORNEYS May 7, 1968 8. w. WEISEL GRINDING WHEEL DRESSING APPARATUS 3 Sheets-Sheet 3 Filed March 3, 1966 4 M M 6 2 w, \L 2 w a M Z 0 2W 5 a w M Z w w z 11/, I \r Ab M Z u W w) z m. 2 6 2 0 0 W a 4 WWW 7 ATTORNEYS United States Patent 3,381,765 GRINDING WHEEL DRESSING APPARATUS Burt W. Weisel, Jackson, Micln, assignor to Camshaft Machine Company, Jackson, Mich, a corporation of Michigan Filed Mar. 3, 1966, Ser. No. 531,592 10 Claims. (Cl. 125-11) The invention pertains to an apparatus for dressing grinding wheels, and particularly relates to a grinding wheel dressing apparatus which is capable of very accurately dressing angularly related surfaces automatically on a grinding wheel face.

The accuracy obtainable in the machining of metal by grinding is largely dependent upon the accuracy obtained in the dressing of the grinding wheel. A great number of grinding wheel dressing devices have been proposed to increase the accuracy and effectiveness of the wheel dressing operation. In particular, a number of dressing devices are available for forming a convex radius upon a grinding wheel face and the invention is concerned with the dressing of a radius upon a grinding wheel and the dressing of the wheel surfaces adjacent the radius.

When grinding angularly related surfaces which intersect, it is usually desired that intersection of the surfaces be formed with a radius of a predetermined dimension. As the radius of such a surface to be formed by grinding can be determined only by the manner in which the grinding wheel is dressed, it is of utmost importance to have grinding wheel dressing apparatus which is capable of forming a radius at the intersection of angularly related surfaces on the grinding wheel. In the past it has been the usual practice to use a linearly movable dressing tool to shape the angularly related surfaces and then dress the radius at the intersection of the surfaces by hand in a trial and error manner.

It is an object of the invention to provide a grinding wheel dressing apparatus which is capable of very accurately, automatically dressing angularly related surfaces upon the grinding face of a grinding wheel, and wherein a radius may be very accurately formed on the grinding wheel at the intersection of the angularly related surfaces.

An additional object of the invention is to provide a grinding wheel dressing apparatus employing a track and movable carriage for a dressing tool wherein the drive mechanism for the dressing tool is of such character as to permit the carriage to readily move through a diverse path of movement with a high degree of accuracy.

A further object of the invention is to provide a grinding wheel dressing apparatus capable of automatic operation wherein effective protection of the moving components of the apparatus is provided by means of a dust cover and movable dust shield.

Another object of the invention is to provide a grinding wheel dressing apparatus wherein the apparatus includes a track and a dressing tool carriage guided by the track wherein the track follower of the carriage provides an effective guiding relationship between the carriage and track for following either linear or convex track portions.

Yet another object of the invention is to provide a grinding wheel dressing apparatus in accord with the invention wherein the dressing tool includes a diamond mounted within a rotatable holder and indexing means are provided to index the holder during each cycle of operation.

These and other objects of the invention arising from the details and relationships of the components of an embodiment thereof will be apparent from the following description and accompanying drawings wherein:

FIG. 1 is a front, elevational view of a grinding wheel dressing apparatus in accord with the invention, portions of the fluid motor support members being broken away 3,381,765 Patented May 7, 1968 and the front support plate being removed for purposes of iliustration,

FIG. 2 is an elevational, sectional view through the grinding wheel dressing apparatus of the invention as taken along section IIII of FIG. 1,

FIG. 3 is an enlarged, detail, elevational, sectional view taken through the dressing tool structure along sec tion III-III of FIG. 1,

FIG. 4 is an enlarged, elevational, sectional view of the track and carriage guide taken along section IVIV of FIG. 3,

FIG. 5 is an enlarged, elevational, sectional view of the track and carriage guide taken along section VV of FIG. 3,

FIG. 6 is a sectional view taken through the support member and dressing tool structure along section VIVI of FIG. 3,

FIG. 7 is a sectional view taken through the dressing tool indexing apparatus, and

FIG. 8 is an elevational view illustrating the relationship of the dressing tool carriage and associated guiding members with the track surfaces during various phases of the dressing operation, two of the positions of the dressing tool carriage being shown in dotted lines.

The dressing apparatus of the invention is adapted to be mounted directly upon a machine utilizing a grinding wheel. For instance, the dressing apparatus may be mounted upon a machine for grinding camshafts, or the like. As the grinding machine, itself, forms no part of the invention, the machine is generally represented by the surface 10, FIG. 1, which serves as the mounting surface for the dressing apparatus. The machine, with which the invention will be used, rotatably supports a grinding wheel 12, which, in the illustrated form, includes linear grinding surfaces 14 and 16 intersecting at a radius 18.

The grinding wheel dressing apparatus is mounted upon a support bracket 20 which may be firmly attached to the grinding wheel machine surface by a plurality of bolts 22. The bracket includes a guideway 24 which, normally, will be disposed in a vertical manner perpendicularly to the axis of rotation of the grinding wheel 12, and a slide 26 is adapted to be accurately, movably positioned within the guideway 24 by means of a threaded feed screw 28 cooperating with the slide-mounted nut 30. The feed screw 28 is rotated by a manually actuatable Wheel and shaft 32 having an indicia dial 34 mounted thereon. Worm gearing within the housing 36 interconnects the shaft 32 with the screw shaft 28 whereby rota tion of the shaft 32 accurately controls the position of the slide 26 in the guideway 24.

A horizontally disposed, dovetail guideway 38 is defined in the slide 26 perpendicular to guideway 24, and, in a conventional manner, may utilize a few screws, not shown, for moving the support member 40 within the slide guideway 38. In this manner the support member 40 may be shifted horizontally with respect to the grinding wheel. Adjustment means are also incorporated in guideway 38 permitting limited angular adjustment of member 40 relative to the axis of the wheel 12. It, therefore, will be appreciated that the multiple compound support of the support member 40 permits the support member to be very accurately moved in both the vertical and horizontal directions relative to the grinding wheel 12.

The support member 40 includes a rear plate 42 which is of a modified, inverted V-configuration, as is best apparent from FIG. 1. The plate 42 includes end portions 44 and a central portion 46 which defines a right angle. A front plate 48, which is of a similar configuration to the plate 42, is maintained in spaced, parallel relation to the plate 42 by three spacers and threaded fasteners 52, FIG. 1. Adjacent the plate 48 on the rearside thereof, i.e., the side of the plate 48 disposed toward the plate 42, a pair of right-angled, or L-shaped, track members 54 and 56 are mounted by screws, not shown. The track members 54 and 56 are very accurately related to each other on the plate 48 and are separated by an L-shaped, elongated slot 58.

The ends of the plate 42 are defined at 60 and a housing 62 is attached to each of these ends of the plates 42 and 48, as shown in FIG. 1. The housings 62 are of a hollow configuration and are adapted to contain the pistons 64 and 66 of expansible motors 68 and 70, respectively, which are mounted upon the housings 62 in substantial, coaxial alignment therewith. The motors 68 and 70 may be of either the air or hydraulic type, and conventional hydraulic expansible motors are preferred.

The pistons 64 and 66 are each attached to the end of a flexible tension member, preferably, in the form of a steel tape 72, which passes between the plates 42 and 48 and is located within the slot 58 defined between the track members 54 and 56. In order to properly align the tape 72 with the slot 58, rollers 74 are rotatably mounted upon the end portions 44 of the plates 42 and 48 on the lower spacers 50 and are tangential to the adjacent portion of the track slot and the direction of movement of the nearest piston.

A pair of rollers 76 are also rotatably mounted on each end portion 44 of the plate 42 on shafts 77, FIG. 1, for guiding an elongated, flexible, dust shield 78. The dust shield 78 may be formed of fabric, leather, or other suitable material, and it has been found that a woven nylon fabric serves very well. Located within each of the housings 62 is a dust shield recoil pulley 80 on which an end of the dust shield is wound and which is biased in the Winding, or recoiling direction by a spiral spring, not shown. This mechanism may be identical to that conventionally employed in drill presses to return the drill press quill to the normal nondrilling position. The dust shield dispensing and recoil pulleys 80 may include means for varying the tension within the recoil spring, if desired, in the manner employed with drill press return devices, whereby the tension in the shield 78 may be adjusted.

The track members 54 and 56 each include a recess, FIG. 3, defined on the inside thereof adjacent the slot 58. The recess Within the track element 54 includes a guide surface 82 facing the slot 58, and the recess defined in the track member 56 includes a guide surface 84 facing the slot 58. As the guide surfaces 82 and 84 both face the slot 58, it will be appreciated that the guide surfaces are in opposed relation and, as will be apparent from FIGS. 3, 4, and 8, the guide surfaces 82 and 84 are in a parallel, equally spaced relationship throughout their length. The guide surfaces 82 and 84, together, define a track having ends disposed adjacent the ends of the members 54 and 56, FIG. 1.

As best appreciated from FIGS. 1 and 8, the guide surface 82 includes perpendicularly related linear surfaces 86 and 88 interconnected by a concave, cylindrical segment radius 90. The guide surface 84 of the track member 56 includes perpendicularly disposed, linearly related guide surfaces 92 and 94 interconnected by a convex, cylindrical segment radius 96. The radii 90 and 96 are concentric, having a common center as represented at 98, FIG. 8.

The grinding wheel dressing tool is mounted upon a carriage 100 adapted to be moved along the track defined by the guide surfaces 82 and 84 of the track members. The carriage 100 is of a U-shaped configuration, FIGS. 6 and 7, including a pair of spaced, parallel plate portions 102 which are interconnected by a bridge portion 104 which rigidly interconnects the plate portions and maintains the spacing thereof. The bridge portion 104 has a configuration which will be appreciated from FIGS. 4 and 8 and includes a surface 106 perpendicularly disposed to the plane of the plate portions 102. The portion 104 comprises a guide portion having a cylindrical segment surface 108 having a radius which corresponds to that of the track radius 90. The cylindrical surface 108 is adapted to be associated with the track guide surface 82 and, in order to reduce the friction With the surface 82, rollers 110 are rotatably mounted within cylindrical recesses defined in the carriage portion 104 located adjacent the surface 108 as to slightly extend therefrom for direct engagement with the track surface 82. Five rollers 110 are employed, including a center roller which is contrally related with respect to the width of the guide member portion 104.

A second guide member 112 is affixed to the carriage 109 and has a U-shaped configuration, including a bridge portion 114 having leg portions 116 depending therefrom, adapted to be afiixed to the plate portion 102 by screws 118. The member 112 is formed with a flat guide surface 120 adapted to engage the track guide surface 84. The opposite. side of the member 112 is formed with a convex, cylindrical segment surface 122 which is concentric with the track radii and 96, and the guide surface 108, when the carriage is disposed in the track, as shown in FIG. 4.

The dimensions of the carriage bridge portions 104 and 114 are such that the surface 122 is tangential with the linear portions of the tape slot 58 when the carriage is in the position shown in FIG. 4, i.e., halfway around the radius or curve of the track. As will be apparent from FIG. 3, the upper half of the tape 72 extends into the slot 58 defined between the track members 54 and 56 and the lower half of the tape width extends into a recess defined by the surfaces 106 and 122. The bolt 124 extending through the member 112 and a hole in tape 72 firmly affixes the tape 72 to the carriage 100 at the midpoint of the carriage portion 104, with respect to its width. Thus, movement of the tape 72 within the slot 58 will pull the carriage 100 between the plates 42, and 48 along the track defined by the guide surfaces 82 and 84. The distance separating the surface and the outer edges of the rollers 110 are very accurately related to the spacing of the surfaces 82 and 84, whereby a very accurate guiding of the carriage along the track defined by the surfaces 82 and 84 is achieved.

The grinding wheel dressing tool mechanism is carried by, and mounted within, the carriage 100. The dressing tool support apparatus includes a reference member 126 adapted to slide between the plate portions 102 of the carriage adjacent the portions 104 and 114 and between portions 116. The reference member 126 includes a convex, cylindrical segment surface 128 adapted to be disposed adjacent the track surface 82. This surface is of a configuration similar to that of the radius 90, and three recesses are defined therein for receiving antifriction rollers 130 which project slightly beyond the surface 128 for direct engagement with the track guide surface 82. The opposite end of the reference member 126 is provided wtih a fiat surface 132 adapted to engage the track guide surface 84. The dimension between the surface 132 and the central roller 130 is such that a very accurate guiding of the reference member 126 within the track is produced. A recess 134 is defined in the member 126 in which a compression spring 136 is mounted. A plug 138 is reciprocally mounted within the recess 134 and is engaged on one side by the spring 136 and engages the track surface 84 on the other side. The spring 136 thereby tends to bias the rollers 130 toward the track surface 82.

The reference member 126 includes a dovetail guide portion 140 disposed toward plate 42. A dressing tool holder 142 of a rectangular configuration, FIG. 6, is slidably mounted between the carriage portions 102 and includes a dovetail recess for mating cooperation with the dovetail portion 140 of the reference member. The reference member 126 is provided with a one-half cylindrical, threaded bore 144, and the holder 142 is provided with. a one-half cylindrical bore 146 which is not threaded. An abutment surface 148 defines the end of bore 146 whereby a screw 150 may be received within the complete cylindrical bore defined by the partial, but aligned, bores 144 and 146, and which is of a length adapted to engage the abutment surface 148 and align at the other end with the surface 152 of the holder 142. An end plate 154 is mounted upon the holder surface 152 by screws 156 and includes a hole 158, aligned with screw 150, whereby a wrench may be inserted through the hole into a hexagonal socket defined in the screw 150. As the end of the screw 150 bears against the inside of the plate 154 when the other screw end engages abutment 148, it will be appreciated that rotation of the screw will cause the dressing tool holder 142 to move up or down relative to the reference member 126, as shown in FIG. 3. It will be appreciated that such adjustment of the dressing tool holder 142 relative to the reference member in a vertical direction will move the dressing tool in a direction transverse to the direction of movement of the carriage 100. A wear plate 160 is mounted on the underside of the carriage plate portions 102 whereby wear between these components, the holder 142, and the plate 42 is minimized.

The grinding wheel dressing tool 162 includes a shank 164 mounted within a cylindrical sleeve 166. The sleeve 166 is rotatably mounted within a cylindrical bore 168 defined in the holder 142. As will be apparent from FIG. 3, the bore 168 is obliquely related to the vertical axis. The lower end of the dressing tool shank 164 is provided with a diamond dressing point 170. The upper end of the dressing tool shank is provided with threads which mate with threads defined in the upper end of the bore of sleeve 166 and also receive lock nuts 172. The index wheel 174 is threaded on sleeve 166 and includes a plurality of index ratchet notches 176 defined thereon, and the outer periphery of the index wheel is provided with a plurality of flats 178 which are for the purpose of engaging a spring detent, as will be later described.

The lower edges of the plates 42 and 48 are in alignment and a cover 180 of sheet metal is attache-d to and interposed between the plate lower edges to protect the space between the plates and the dressing tool apparatus from the dust and debris occurring during the dressing operation. In order to permit the dressing tool point 170 to have access to the grinding wheel 12, an elongated opening 182 is defined in the cover 180, and it will be appreciated that the opening extends throughout the length of the track member 56. In order to prevent the fine grinding wheel dust and other abrasive foreign matter from entering between the plates 42 and 43 through the opening 182, the elongated, flexible, dust shield 78 previously described is disposed adjacent the opening 182 and is attached to the dressing tool by a collar 184 surrounding the shank 164. The width between the longitudinal edges of the dust shield 78 is slightly greater than the spacing separating the plate 48 and the track member 56, FIG. 3, whereby a close fitting sliding engagement between the dust shield and these components is provided, which will prevent the grinding dust and foreign matter from entering the space between the plates 42 and 48. As the carriage 100 moves along its track, the dust shield 78 will be retained taut by the associated recoil pulleys 80 in all positions of movement of the carriage.

Indexing of the grinding wheel dressing tool 162 is produced by an index detent 186 mounted on the plate 42. The location of the index detent 186 will be appreciated from FIG. 1 wherein the detent is shown in dotted lines. The detent is located near the end of the track defined by the guide surfaces 82 and 84 whereby indexing of the dressing tool will be accomplished during each complete cycle of operation and at a time when the dressing tool point 170 is not in engagement with the grinding wheel. The indexing detent apparatus includes a bracket 138, FIG. 7, which is mounted on the plate 42 by a pair of bolts 190. An annularly extending bracket projection 192 is internally threaded to receive a threaded plug 194 having a central opening defined therein. The index detent pin includes a rectangular cross section portion 196 extending through corresponding rectangularly shaped hole 198 defined in the plate 42. The portion 196 defines a shoulder at 200 and the index pin portion 202 is cylindrical and is threaded for cooperation with the threads of a knob 204 engaging the end of projection 192. A compression spring 206, interposed between the shoulder 200 and the plug 194, tends to bias the index pin in the direction which will produce engagement of the beveled detent point 208 with the index wheel 174. It will be appreciated that movement of the detent pin in the direction for engagement with the index wheel is limited by the adjustment of the knob 204 on the threaded portion 202.

A spring steel clip 210 is afiixed to the end plate 154 by the screws 156 which afiix the plate to the dressing tool holder 142. The spring clip 210 includes a resilient portion 212 which engages the flats 178 of the index wheel 174 to resist rotation of the dressing tool and to maintain the dressing tool in the selected rotational position as produced by the index wheel engagement with the indexing detent.

The dressing tool 162 and the tool holder 142 are accurately related wherein the diamond point 170 is accurately positioned relative to the tool holder by adjustment of the shank 164 in the threads of the sleeve 166, and this adjustment is maintained by the lock nuts 172 on the dressing tool shank. The diamond point is related to the tool holder 142 so that when the adjustment screw 150 is rotated to engage the end plate 154 with the surface 152 of the reference member 126, the tip of the diamond point 170 will be located at the center 98 of the track radii and 96 when the carriage is located in the curved position of the track, as in FIG. 4. Thus, with the plate 154 and surface 152 in engagement, movement of the carriage through the track defined by the guide surfaces 82 and 84 would cause the diamond point to describe a right angle having no radius at the intersection of the linear directions of movement. With reference to FIG. 8, the grinding wheel surfaces 14 and 16 represent the direction of movement of the diamond tip as the carriage moves through the linear track portions defined by the linear guide surfaces 36 and 92; and 88 and 94, respectively. If the diamond point 170 is set to coincide with the center 98 of the track radii 90 and 96, as described above, the diamond point will not define a radius at the intersection of the surfaces 14 and 16, but, rather, will define a sharp 90 angle in the form of a point at this location.

Normally, it is desired to define a cylindrical, convex curve of a predetermined radius at the intersection of the surfaces 14 and 16, and this procedure is readily accomplished in accord with the invention by offsetting the diamond point 176 from center 98 by the desired radius. This adjustment is made by inserting a wrench through the plate hole 158 into screw and rotating the screw 150 to shift the dressing tool holder 142 relative to the reference member 126. Rotation of the screw 150 separates the end plate 154 and surfaces 152. Preferably, the adjustment of the dressing tool holder 142 relative to the reference memher 126 is accurately accomplished and maintained by means of a shim block 214 of a size equal to the desired dressing radius inserted between the surface 152 and plate 154. For instance, if it is desired that the grinding wheel be dressed with a radius 18 of onesixteenth of an inch, a one-sixteenth of an inch shim block 214 will be placed between the surface 152 and end plate 154, and the screw 15%) rotated to firmly engage the plate 154 with the shim. In this manner, the diamond tip will be very accurately located with respect to the center 98 of the track radii by one-sixteenth of an inch and, thus, the diamond point will describe a line of movement having a radius of onesixteenth of an inch as the carriage moves around the track radii 90 and 96.

In operation, the dressing tool support member 40 will be removed from proximity with the grinding wheel 12, as the operator will have rotated the hand wheel and shaft 32 to elevate the slide 26, that the grinding wheel may be used in the normal manner to grind workpieces. A grinding wheel 12 of the disclosed type is employed in the manu facture and finishing of camshafts, and the radius 18 of the grinding wheel is used to define a fillet on a camshaft which is tangent with a bearing surface and a radially disposed locating surface. To minimize the occurrence of stress locations, it is important that the fillet formed on the camshaft be accurately ground and shaped. Therefore, it is necessary to redress the grinding Wheel after grinding a predetermined number of camshafts.

When it is desired to redress the grinding wheel, the operator rotates the hand wheel 32 to lower the slide 26 and the support member 48 toward the grinding wheel 12. By means of the indicia dial 34, the operator is able to determine the desired position of the support member. At this time the carriage 190 will be located adjacent one end of the track defined by the track surfaces 82 and 84, as the piston of the right motor 70, for instance, will be fully retracted, while the piston of the left expansible motor 68 will be fully extended. With the carriage disposed adjacent the right end of the track, FIG. 1, the diamond point 170 may be carefully brought into engagement with the grinding wheel surface 14 by rotation of the wheel 32. If it is desired to take a two-thousandths of an inch dressing cut across the grinding wheel, the operator will rotate the hand wheel 32 sufiiciently to cause the diamond point to penetrate the grinding wheel surface such a distance. Once the support member 49 is accurately related to the grinding wheel in the desired manner, the expansible motor 68 will be energized by an appropriate valve, not shown, which causes the piston 64 to begin retracting into the motor 68 and thereby pulls the tape 72 to the left, FIG. 1. Movement of the tape 72 to the left FIG. 1. Movement of the tape 72 to the left pulls the carriage 100 in a like direction and causes the carriage 100 and the reference member 126 to begin traversing the linear track guide surfaces 86 and 92 moving the diamond point 170 in a linear direction to dress the grinding wheel surface 14.

Due to the flexible nature of the tape 72, as the carriage 100 enters the track portion defined by the guiding surface radii 90 and 96, the carriage 100 will continue to move through the track around the radii and cause the diamond point to travel through an are having a one-sixteenth of an inch radius and, thus, dress the radius 18 of the grinding wheel. The carriage 100 and reference member 126 will then leave the track radii and enter the track guide surface linear portions 88 and 94 to cause the diamond point to again travel through a linear path and dress the grinding wheel surface 16. The path of movement of the diamond tool and carriage during this operation will be appreciated from FIG. 8.

As the carriage 100 moves along the track, the motor 70 will be valved to an exhaust position whereby the tension in the tape 72 will pull the piston rod 66 toward an extended position. Simultaneously, the movement of the carriage 100 will cause the dust shield 78 to move in a longitudinal direction recoiling the dust shield upon the left recoil pulley 80 and withdrawing the dust shield from the right pulley 80, FIG. 1.

Upon the carriage 100 approaching the extreme left end of the guide surfaces 88 and 94, FIG. 1, a notch 176 of the index wheel 174 will engage the index detent point 208, causing the index wheel to rotate through an increment and thereby prepare a new surface of the diamond point 170 for the next engagement with the grinding wheel. Limit switches, or limit valves, are preferably employed with the apparatus sensing the position of one or both of the piston rods 64 or 66 to automatically deenergize the motor 68 when the dressing operation is complete. By regularly rotating the dressing tool, a new surface will continually be presented to the dressing wheel and, thus, the wear on the diamond point will be even, and maximum life and the best dressing characteristics can be obtained from the diamond point.

The index detent is located so that rotation of the dressing tool occurs after the surface 16 is dressed and the point is not in engagement with the wheel.

After the dressing operation, the operator will rotate the wheel 32 to retract the support member 40 from the grinding wheel if it is not desired to take another dressing cut. If it is desired to run the diamond point 170 across the grinding wheel surfaces again, the hand wheel 32 is rotated to lower the support 40 about twothousandths of an inch, and the motor is pressurized and the motor 68 exhausted. This operation moves the tape 72 and carriage to the right, FIG. 1, and returns the carriage 190 to the initial starting position. As the carriage initially begins to move toward the starting position, the movement of the carriage and index wheel 174 past the detent point 208 will retract the detent pin from the index wheel, in that the oblique surface defined upon the point will engage the index wheel and, thus, cause the spring 206 to compress slightly and retract the detent pin from a noninterfering relationship with the index wheel.

While the configuration of the track shown consists of a pair of perpendicularly disposed linear portions interconnected by a radius. it will be appreciated that other configurations of track may well be utilized within the concept of the invention. By the use of the convex surface 108 and the convex relationship defined by the rollers 110, and the use of the opposed linear surface 126, the carriage 100 is capable of being very closely guided within the track surfaces 82 and 84 through both linear and arcuate track configurations. With reference to FIG. 8, it will be noted that when the carriage 190 is moving through a linear portion of the track, the surface 120 will be in full engagement with the linear track portion defined on the track member 56 and only the central roller 110 will be engaging the linear track portion defined on the track member 54. As the carriage 100 moves through the arcuate portions of the track, all of the rollers 110 will engage the radius 90, while only a line contact will exist between the surface and the track radius 96. Thus, the configuration of the surfaces defined on the carriage which cooperate with the track permits a free sliding of the carriage within the track as the carriage moves through both linear and arcuate paths of movement, and the use of the flexible tape 72 for moving the carriage produces a uniform movement of the carriage as it passes through all of the track portions.

As the reference member 126 also includes a convex surface 128 and rollers 130, including a central roller, and includes an opposed linear surface 132, the reference member 126 will operate in a similar manner relative to the track guide surfaces. However, as the reference member 126 includes the biasing spring and plug 138, the spring will always maintain the central roller 130 in engagement with the track guide surface defined in the track member 54 and, thus, the guide surface 82 will constitute the actual reference surface which determines the position of the reference member 126. Cocking of the reference member 126 relative to the track is prevented by the close sliding relationship of the reference member within the carriage 100. Likewise, the close sliding reception of the dressing tool holder 142 between the portions 102 of the carriage prevents the tool holder from cocking relative to the carriage.

It will be appreciated that in the practice of the invention the cylindrical radius defined by the surfaces 108 and 128, or the points of contact defined by the rollers 110 and 130 within the track, preferably corresponds to the minimum radius defined in the track 82 whereby engagement of all the rollers with the cylindrical track radius 90 will occur as the carriage travels through the minimum radius of movement defined by the carriage.

As the tape slot 58 is of a configuration corresponding to that of the track defined by surfaces 82 and 84, the slot 58 closely guides the tape 72-, producing a pull on the carriage transverse to the length of the carriage 100 and permits the carriage to readily move through the track configuration. The cylindrical surface 122 will fully engage the tape 72 while the carriage is moving about the track radius, whereby the tape will not bind in the slot .58 in the track radius and the tape 72 permits an effective driving force to be applied to carriage 100 even though the track configuration may be relatively complex.

It will be appreciated that various modifications to the invention may be apparent to those skilled in the art without departing from the spirit and scope thereof, and it is intended that the invention be defined only by the scope of the following claims.

I claim:

1. Grinding wheel dressing apparatus comprising, in combination,

(a) a support member,

(b) a track defined on said support member, said track including a pair of spaced, parallel guide surfaces and having first and second ends,

(c) a carriage mounted for movement along said track,

said carriage including guide members closely, slidably engaging said track guide surfaces,

((1) a dressing tool support mounted upon said carriage for selective adjustment in a direction transverse to the direction of movement of said carriage,

(e) a grinding wheel dressing tool mounted upon said tool support having a dressing point mounted thereon,

(f) a flexible, elongated, tension member mounted on said support member having a central portion disposed adjacent said track and affixed to said carriage and end portions extending beyond the ends of said track,

(g) means guiding said tension member central portion adjacent said track to form said tension member central portion into a configuration substantially similar to that of said track, and

(h) tension member actuating means mounted on said support member associated with said tension member end portions adapted to axially translate said tension member and move said carriage along said track.

2. In a grinding wheel dressing apparatus as in claim 1 wherein:

(a) said means guiding said tension member central portion comprises an elongated slot defined in said support member parallel to said track guide surfaces, said tension member being axially, slidably received within said slot.

3. In a guiding wheeel dressing apparatus as in claim 1 wherein:

(a) said tension member actuating means comprises a pair of expansible motors mounted on said support member, said motors each including a reciprocable piston, one end portion of said tension member being connected to one of said motor pistons and the other tension member end portion being connected to the other motor piston.

4. In a grinding wheel dressing apparatus as in claim 1 wherein:

(a) said track spaced, parallel guide surfaces are in opposed relation and include a first surface and a second surface,

(b) said carriage guide members including a first flat guide surface disposed in the direction of said dressing point adapted to engage said track first surface and a second guide surface adapted to engage said track second surface,

(c) said second guide surface being of a convex, partially cylindrical configuration having a radius substantially corresponding to the smallest radius defined in the configuration of said track second surface.

5. In a grinding wheel dressing apparatus as in claim 4 wherein:

(a) said dressing tool support includes a reference member having a reference surface defined thereon adapted to engage said track second surface,

(b) biasing means biasing said reference member toward said track second surface maintaining said reference surface in engagement therewith,

(c) a guideway defined on said reference member transversely disposed to the direction of movement of said carriage,

(d) said dressing tool support including a dressing tool holder guidingly mounted for movement upon said guideway, said dressing tool being mounted upon said holder, and

(e) adjustment means interposed between said reference member and said tool holder adapted to adjust said tool holder relative to said reference member.

6. In a guiding wheel dressing apparatus as in claim 5 wherein:

(a) said reference member reference surface is of a convex, partially cylindrical configuration having a radius substantially equal to the smallest radius defined in said track second surface.

7. In a grinding wheel dressing apparatus as in claim 1:

(a) means rotatably mounting said dressing tool upon said tool support,

(b) an index wheel mounted on said dressing tool concentric with the axis of rotation thereof,

(c) detent engageable means defined on said index wheel evenly spaced about the periphery thereof, (d) an indexing detent mounted on said support member adjacent one end of said track adapted to engage and rotatably index said index wheel upon movement of said carriage thereby, and

(e) retaining means mounted on said dressing tool support engaging said index wheel maintaining selective, rotational positioning of said index tool.

8. In a grinding wheel dressing apparatus as in claim 1:

(a) said support member including a pair of spaced plates each having an edge adapted to be disposed toward the grinding wheel to be dressed, said carriage, tool supported and dressing tool being located in the space between said plates,

(b) a cover affixed to and extending between said edges of said plates,

(c) an elongated opening defined in said cover, said dressing point extending through said elongated open- (d) an elongated flexible dust shield disposed between said spaced plates located adjacent said cover, said shield being disposed intermediate said elongated cover opening and said dressing tool carriage and afiixed to said carriage for movement therewith, and

(e) recoil shield storage means mounted on said support member adjacent each end of said track adapted to dispense and recoil said dust shield in accordance with the direction of movement of said carriage.

9. Grinding wheel dressing apparatus comprising, in

combination,

(a) a support member,

(b) a track defined on said support member, said track consisting of a pair of opposed, spaced, guide surfaces, said surfaces including parallel, spa-ced, opposed linear portions and concentric, arcuate, concave and convex portions tangentially related to and intersecting said linear portions,

(0) a carriage mounted for movement along said track,

a convex guide member surface defined on said carriage adapted to slidingly engage said track concave and linear portions, a linear guide member surface defined on said carriage adapted to slidingly engage said track convex and linear portions, said convex and linear guide member surfaces being defined in spaced, opposed relation upon said carriage,

(d) a dressing tool support mounted upon said carriage for selective adjustment in a direction transverse to the direction of movement of said carriage,

(e) a grinding wheel dressing tool mounted upon said tool support having a dressing point mounted thereon, and

(f) means drivingly connected to said carriage adapted to translate said carriage along said track.

10. In a grinding wheel dressing apparatus as in claim 9 wherein:

(a) said means drivingly connected to said carriage includes a flexible tension member affixed to said support member having a central portion disposed adjacent said track and connected to said carriage and end portions extending beyond the ends of said track,

(b) means guiding said tension member central portion adjacent said track to form said tension member cen- References Cited UNITED STATES PATENTS Alvord 12511 Turner 12511 Johnson 12511 Porcello 125-11 Frank 125-114 X HAROLD D. WHITEHEAD, Primary Examiner. 

1. GRINDING WHEEL DRESSING APPARATUS COMPRISING, IN COMBINATION, (A) A SUPPORT MEMBER, (B) A TRACK DEFINED ON SAID SUPPORT MEMBER, SAID TRACK INCLUDING A PAIR OF SPACED, PARALLEL GUIDE SURFACES AND HAVING FIRST AND SECOND ENDS, (C) A CARRIAGE MOUNTED FOR MOVEMENT ALONG SAID TRACK, SAID CARRIAGE INCLUDING GUIDE MEMBERS CLOSELY, SLIDABLY ENGAGING SAID TRACK GUIDE SURFACES, (D) A DRESSING TOOL SUPPORT MOUNTED UPON SAID CARRIAGE FOR SELECTIVE ADJUSTMENT IN A DIRECTION TRANSVERSE TO THE DIRECTION OF MOVEMENT OF SAID CARRIAGE, (E) A GRINDING WHEEL DRESSING TOOL MOUNTED UPON SAID TOOL SUPPORT HAVING A DRESSING POINT MOUNTED THEREON, (F) A FLEXIBLE, ELONGATED, TENSION MEMBER MOUNTED ON SAID SUPPORT MEMBER HAVING A CENTRAL PORTION DISPOSED ADJACENT SAID TRACK AND AFFIXED TO SAID CARRIAGE AND END PORTIONS EXTENDING BEYOND THE ENDS OF SAID TRACK, (G) MEANS GUIDING SAID TENSION MEMBER CENTRAL PORTION ADJACENT SAID TRACK TO FORM SAID TENSION MEMBER CENTRAL PORTION INTO A CONFIGURATION SUBSTANTIALLY SIMILAR TO THAT OF SAID TRACK, AND (H) TENSION MEMBER ACTUATING MEANS MOUNTED ON SAID SUPPORT MEMBER ASSOCIATED WITH SAID TENSION MEMBER END PORTIONS ADAPTED TO AXIALLY TRANSLATE SAID TENSION MEMBER AND MOVE SAID CARRIAGE ALONG SAID TRACK. 